It is well known to use articulated arms to transport semiconductor wafers, plates and flat panel displays between cassettes, load locks, process modules and other work stations. Recent developments in the processing of semiconductors include the introduction of chemical metal polishing (CMP) and copper deposition whereby articulated arms can be exposed to fluids, corrosive liquids and corrosive gasses. These fluids, corrosive liquids and corrosive gasses can infiltrate the drive mechanism for the articulated arm causing premature failure of mechanical and electrical components due to contamination and corrosion. In the past, the drive mechanism has been sealed typically using bellows, lip seals, labarinth seals or ferro-fluid type seals; each of these sealing types has been effective but can be costly or also requiring high precision machining and alignment of sealing components.
The apparatus of the present invention relates generally to material transfer devices. The material transferred might include, but is not limited to semiconductor wafers, such as Silicon, Gallium Arsenide, semi conductor packing substrates, such as high density interconnects, semiconductor manufacturing process imaging plates, such as masks or reticles, and large area display panels, such as Active Matrix LCD substrates or Field Emission Diode substrates.
The invention further relates to robot drive technologies for handling wafers or flat panels and relates more particularly to improvements in such technologies whereby fluids, gasses, and contaminants can be isolated and excluded from the robot drive mechanism. The invention further relates to seals for rotating and/or reciprocating shafts and, more particularly, to low friction gas and liquid exclusion seals for rotating and/or reciprocating shafts.
The invention resides in a seal assembly for use in semiconductor manufacturing automation and more specifically relates to an improvement therefor whereby the robot drive mechanism can be sealed and isolated from fluids, gasses, and contaminants without the use of bellows, lip seals, labarinth seals or ferro-fluid type seals.
More specifically, the invention resides in a noncontact isolation seal assembly for rotary and linear sealing for use in semiconductor manufacturing automation. The noncontact isolation seal assembly comprises a seal having an aperture with a shaft extending through the aperture. A gap region is maintained between the outside surface of the shaft and the aperture of the seal. A gas source is connected to the interior of the gap region whereby gas pressure in the gap region is maintained at a higher pressure than gas pressure surrounding the shaft. The flow of gas and differential pressure prevents fluids, gasses, and contaminants from passing through the gap region preventing contamination of the drive mechanism.